I have three office connect with site to site VPN. Each office has Cisco asa5505. All has been setup and work fine for more than a year. Recently, I change one of the office public IP address (officeA). It works fine for couple days. One day, it suddently drop the connection. I cannot ping from officeB to any IP in officeA. And I check the VPN session from Cisco ADSM console (from monitoring). The connection still established.
After a while troubleshooting, I found I have to "Logoff" the session. And then the connection will re-establish after couple second.
As describtion, we have three office. So, officeC VPN connection to officeA are okay. Never drop the connection.
Does anyone has this issue? Any comment or suggestion are highly appriciated.
The issue requires some debugging in order to verify in which state the connection is found, you will need to install a syslog server and send some logs to verify the problem at a time to have it, also, please issue the following commands at a time to have the problem on both sides
show crypto isakmp sa
show crypto ipsec sa
If the problem came out after maybe changing the ISP with no other change we could verify and external problem but we need to prove it